Typical Composition of Wastewater Sludges

Untreated

Component

Primary

Digested

Total solids (TS; %)

5

10

Volatile solids (% of TS)

65

40

pH

6

l

Alkalinity (mg/L as CaCO3)

600

3000

Cellulose (% of TS)

10

10

Grease and fats (ether soluble; % of TS)

6-30

5-20

Protein (% of TS)

25

18

Silica (SiO2; % of TS)

15

10

Source: Metcalf & Eddy, Wastewater Engineering: Treatment, Disposal, and Reuse, 3rd ed., McGraw-Hill, New York, 1991. With permission.

TABLE 9.3

Nutrients and Metals in Typical Wastewater Sludges

TABLE 9.3

Nutrients and Metals in Typical Wastewater Sludges

Component

Median

Mean

Total nitrogen (%)

3.3

3.9

NH+ (as N; %)

0.09

0.65

NO3- (as N; %)

0.01

0.05

Phosphorus (%)

2.3

2.5

Potassium (%)

0.3

0.4

Mean

Standard Deviation

Copper (mg/kg)

l41

962

Zinc (mg/kg)

1200

1554

Nickel (mg/kg)

43

95

Lead (mg/kg)

134

198

Cadmium (mg/kg)

l

12

PCB-1248 (mg/kg)

0.08

1586

Source: Data from USEPA (1983, 1990) and Whiting (1975).

TABLE 9.4

Pond Sludge Accumulation Data Summary

Facultative Ponds (Utah)

Aerated Ponds (Alaska)

TABLE 9.4

Pond Sludge Accumulation Data Summary

Facultative Ponds (Utah)

Aerated Ponds (Alaska)

Parameter

A

B

C

D

Flow (m3/d)

37,850

694

681

284

Surface (m2)

384,188

14,940

13,117

2520

Bottom (m2)

345,000

11,200

8100

1500

Operated since last cleaning (yr)

13

9

5

8

Mean sludge depth (cm)

8.9

7.6

33.5

27.7

Total solids (g/L)

58.6

76.6

85.8

9.8

Volatile solids (g/L)

40.5

61.5

59.5

4.8

Wastewater, suspended solids (mg/L)

62

69

185

170

Source: Schneiter, R.W. et al., Accumulation, Characterization and Stabilization of Sludges from Cold Regions Lagoons, CRREL Special Report 84-8, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, NH, 1984. With permission.

Source: Schneiter, R.W. et al., Accumulation, Characterization and Stabilization of Sludges from Cold Regions Lagoons, CRREL Special Report 84-8, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, NH, 1984. With permission.

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